title: Causes and frequency of unplanned hospital readmission after total hip arthroplasty.
abstract: BACKGROUND
  Total hip arthroplasty (THA) is a beneficial and cost-effective procedure for patients with osteoarthritis. Recent initiatives to improve hospital quality of care include assessing unplanned hospital readmission rates. Patients presenting for THA have different indications and medical comorbidities that may impact rates of readmission.
  
  
  OBJECTIVE
  This study measured (1) the unplanned hospital readmission rate in primary THA, revision THA, and antibiotic-spacer staged revision THA to treat infection. Additionally, we determined (2) the medical and surgical causes of readmission; and (3) the risk factors associated with unplanned readmission.
  
  
  METHODS
  A total of 1415 patients (988 primary THA, 344 revision THA, 82 antibiotic-spacer staged revision THA to treat infection) from a single institution were included. All hospital readmissions within 90 days of discharge were reviewed. Patient demographics and medical comorbidities were included in a Cox proportional hazards model to assess risk of readmission.
  
  
  RESULTS
  The overall unplanned readmission rate was 4% at 30 days and 7% at 90 days. At 90 days, primary THA (5%) had a lower unplanned readmission rate than revision THA (10%, p < 0.001) and antibiotic-spacer staged revision THA (18%, p < 0.001). Medical diagnoses were responsible for almost one-fourth of unplanned readmissions, whereas over half of surgical readmissions were the result of dislocation, surgical site infection, and postoperative hematoma. Type of procedure, hospital stay greater than 5 days, cardiac valvular disease, diabetes with end-organ complications, and substance abuse were each associated with increased risk of unplanned readmission.
  
  
  CONCLUSIONS
  Higher rates of unplanned hospital readmissions in revision THA rather than primary THA suggest that healthcare quality measures that incorporate readmission rates as a proxy for quality of care should distinguish between primary and revision procedures. Failure to do so may negatively impact tertiary referral hospitals that often care for patients requiring complex revision procedures.
authors.affiliation: Department of Orthopaedic Surgery, University of California San Francisco, 500 Parnassus Avenue, MU 320W, San Francisco, CA, 94143-0728, USA.
authors.forename: William W
authors.initials: WW
authors.lastname: Schairer
authors.forename: David C
authors.initials: DC
authors.lastname: Sing
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Vail
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Bozic
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation; D016009:Chi-Square Distribution; D005260:Female; D006621:Hip Joint / Q000601:surgery*; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D010359:Patient Readmission; D011183:Postoperative Complications / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D016016:Proportional Hazards Models; D016459:Prosthesis-Related Infections / Q000175:diagnosis / Q000209:etiology / Q000601:surgery; D058996:Quality Improvement; D019984:Quality Indicators, Health Care; D012086:Reoperation; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents